1. Field of Invention
This invention relates, generally, to a tubular lining material for lining pipes in need of repair or structural reinforcement.
2. Description of the Prior Art
Conventional pipe repair requires that the pipe be dug up and replaced. However, inventors have developed elongate inflatable bladders that can be inserted into a pipe at an access point and then inflated so that the bladder is inverted upon entering the pipe. More particularly, the mouth or leading end of a bladder is attached to the open end of a pipe. The trailing end of the bladder is then inserted into the pipe, thereby inverting the bladder. The bladder provides a substrate for a curable resin that abuts the interior walls of the pipe when the bladder is inflated. The repair is complete when the resin has cured.
Inversion of the bladder is not needed when lining a pipe that is open at both ends. Insertion by inversion is needed when lining lateral pipes (pipes that form a T-intersection with other pipes or any other pipe that cannot be easily accessed from both ends.
The liners that have been developed are difficult and expensive to manufacture because the liners include a support layer sandwiched between two sealing layers. This arrangement of parts interferes with absorption by the sealing layer of the curable resin (known as “wetting”). The curable resin is absorbed relatively quickly by the sealing layer until the curable resin reaches the support layer that is embedded in the support layer.
There is a need for a liner that is free of the wetting problem.
However, it was not obvious to those of ordinary skill in the art, in view of the prior art considered as a whole at the time the present invention was made, how the wetting problem could be overcome.